What Is Bull-Dog Sauce? Tonkatsu Sauce Explained
Bull-Dog is one of the familiar names in Japanese tonkatsu sauce: the thick, fruity brown sauce spooned over breaded pork cutlets, croquettes and fried prawns. It belongs to a family of Japanese sauces that Japan's food standards sort by one simple test: how thick they are.
This guide explains that family, what tonkatsu sauce is made from, and how to use it. It sits inside our Pantry Masterclass.
Our tonkatsu sauce: Bull-Dog Tonkatsu Sauce, 1.8L.
What Is Tonkatsu Sauce?
Japan's Ministry of Agriculture (MAFF) groups these sauces as sōsu-rui (ソース類): liquid seasonings made from vegetable and fruit juices or extracts, with sugar, vinegar, salt and spices as required ingredients. Typical vegetables are tomato, carrot and onion; typical fruits are apple, prune and dates. The ingredients are washed, cut, cooked and sieved, blended with the sugar, vinegar, salt and spices, then matured, filtered and bottled.
Tonkatsu sauce is the thick member of the family, made to sit on a crisp crust rather than soak into it. Tonkatsu itself, with croquettes and curry rice, was one of the three great yōshoku dishes of late Meiji and Taishō Japan: Western dishes reworked to eat with rice.
Source: MAFF JAS committee minutes on sōsu-rui; MAFF OKOME-SUMMARY page on washoku and rice. Facts extracted and reworded.
Worcester, Chūnō or Nōkō: Japan's Three Sauces
Japan's JAS food standard splits these sauces into three by viscosity:
- Worcester sauce (ウスターソース). Thin and sharp: under 0.2 Pa·s.
- Chūnō sauce (中濃ソース). Medium-thick: 0.2 to 2.0 Pa·s.
- Nōkō sauce (濃厚ソース). Thick: 2.0 Pa·s and over. Tonkatsu sauce sits here.
Each has a special grade and a standard grade, with limits on solids and salt, and the special grade also sets a minimum for vegetables and fruit. There are also sauces made for one job, such as okonomiyaki and yakisoba sauce. Tastes differ by region too: MAFF notes that chūnō is the usual sauce from Kantō northwards, while both Worcester and the thick styles are used west of Kinki.
Source: MAFF JAS committee minutes on sōsu-rui (26 August 2014 and 16 July 2024). Facts extracted and reworded.
How to Use Tonkatsu Sauce
- Tonkatsu and chicken katsu. Spoon over the sliced cutlet, with shredded cabbage, rice and miso soup.
- Korokke and fried seafood. The standard sauce for croquettes, fried prawns and fried oysters.
- Katsu sando. Spread on soft white bread with a pork cutlet and a little mustard.
- Beyond Japanese food. Brush onto burgers or sausages, or stir into gravy for a sweet-sour lift.
In the UK, "katsu" often means a curry sauce. In Japan, katsu curry is a cutlet served with Japanese curry; tonkatsu sauce is a separate thing, served with the cutlet on its own.
Popular Products
Bull-Dog Tonkatsu Sauce, 1.8L
The classic thick katsu sauce, in the economy-size handled bottle for kitchens.
Frequently Asked Questions
What is Bull-Dog sauce?
A Japanese brand of fruit and vegetable sauces; its tonkatsu sauce is the thick style served with katsu.
What is the difference between tonkatsu sauce and Worcestershire sauce?
They are the same family. Japanese Worcester sauce is thin and sharp; tonkatsu sauce is the thick (nōkō) style, sweeter and fruitier. Chūnō sits in between.
What is tonkatsu sauce made from?
Vegetable and fruit juices or extracts, such as tomato, onion, apple and prune, with sugar, vinegar, salt and spices.
Is tonkatsu sauce the same as katsu curry sauce?
No. Katsu curry uses Japanese curry; tonkatsu sauce is a thick brown sauce served on its own.
How do I store it?
In a cool, dark place before opening, and in the fridge once opened.
Where to Buy Tonkatsu Sauce in the UK
We stock Bull-Dog Tonkatsu Sauce, with panko and the Otafuku okonomi and yakisoba sauces, and deliver across the UK.
For more, browse the Pantry Masterclass, or read our Shichimi guide.
Sources: Ministry of Agriculture, Forestry and Fisheries of Japan: JAS committee minutes on sōsu-rui (26 August 2014 and 16 July 2024); OKOME-SUMMARY page on washoku and rice; retrieved 5 November 2026; product specifications. Facts extracted and reworded, not reproduced.
